Artificial lift techniques are used to increase the flow rate of oil out of a production well. One commercially available type of an artificial lift is a gas lift. With a gas lift, compressed gas is injected into a well to increase the flow rate of produced fluid by decreasing head losses associated with weight of the column of fluids being produced. In particular, the injected gas reduces pressure on a bottom of the well by decreasing bulk density of the fluid in the well. The decreased density allows the fluid to flow more easily out of the well. Gas lifts, however, do not work in all situations. For example, gas lifts do not work well with a reserve of high viscosity oil (heavy oil). Typically, thermal methods are used to recover heavy oil from a reservoir. In a typical thermal method, steam generated at the surface is pumped down a drive side well into a reservoir. As a result of the heat exchange between the steam pumped into the well and the downhole fluids, the viscosity of the oil is reduced by an order of magnitude that allows it to be pumped out of a separate producing bore. A gas lift would not be used with a thermal system because the relatively cool temperature of the gas would counter the benefits of the heat exchange between the steam and the heavy oil therein increasing the viscosity of the oil and negating the desired effect of the thermal system.
Other examples where gas lifts are not suitable for use are production wells where there are high levels of paraffins or asphaltenes. The pressure drop associated with delivering the gas lift, changes the thermodynamic state and makes injection gases colder than the production fluid. The mixing of the cold gases with the production fluids acts to deposit these constituents on the walls of production piping. These deposits can reduce or stop the production of oil.
For the reasons stated above and for other reasons stated below, which will become apparent to those skilled in the art upon reading and understanding the present specification, there is a need in the art for an effective and efficient apparatus and method of extracting oil from a reservoir.